Ugandan security forces shot and wounded at least seven people today after fire destroyed a royal tomb, heightening tensions between the government and the powerful Bugandan kingdom.

A Reuters witness said the shooting happened when security forces were clearing Bugandan loyalists from the charred remains of the tombs where their royalty are buried, so President Yoweri Museveni could visit the site gutted by fire on Tuesday night.

The cause of the blaze which destroyed the thatched-roof mausoleum and many centuries-old royal artefacts at the UNESCO World Heritage Site has not been identified, but some angry protesters suspected foul play.

"They have a wide conspiracy of destroying everything that marks there was a great kingdom called Buganda, and this is one of them," loyalist Jemba Erisa said at the tombs. The Baganda are Uganda's largest tribe and were instrumental in Museveni coming to power 24 years ago.

President Museveni based his five-year military struggle in the kingdom's heartland and support by the Baganda has helped him stay in power.

But relations have been increasingly strained since Museveni last year blocked the reigning Bugandan monarch, or Kabaka, Ronald Mutebi, from visiting a part of his kingdom. The standoff sparked two days of rioting in the capital Kampala that killed at least 15 people.

Hundreds were arrested and the authorities also shut down the kingdom's radio station for allegedly fanning violence.

Mr Medard Lubega, deputy information minister for the Bugandan kingdom, told Reuters there were unconfirmed reports that three protesters had been killed at the tombs on Wednesday.

The police were not immediately available for comment.

Analysts said the riots last September were unlikely to be the last turmoil before presidential elections in 2011 because Buganda was being used by the opposition as a tool for political mobilisation against Museveni.

Control over resources

The Kabaka wants more autonomous control over resources in his kingdom, such as land and taxes, but the government says he is only a cultural figure and must steer clear of politics.

The violence comes at a time investor interest in east Africa's third biggest economy is increasing following the discovery of an estimated 2 billion barrels of crude oil near the remote western border with Democratic Republic of Congo.

A Bugandan kingdom official, Charles Peter Mayiga, said the gutted mausoleum was built in 1860 by Kabaka Mutesa I and that its historical and cultural significance was an object of deep reverence by the Baganda people.

Oh my!! It is really sad to see such a symbol of (tribal) National pride be burnt to ashes!!

What were they thinking? That the government will lose out by the burning of these tombs? I would think it is the same Baganda who have everything to lose here: for them this is like Egypt without the pyramids!!

Thousands of people have attended the site of a Ugandan royal mausoleum destroyed by fire last week, for the start of a week of mourning. Many people wore traditional clothes, such as white tunics or kanzus and items made from bark cloth.

The burning of the tombs of the Buganda kingdom sparked protests in which at least two people were killed.

Government supporters and Buganda's King Ronald Mutebi have been at loggerheads since riots last year.

The BBC's Joshua Mmali says there were thousands of people both inside and outside the site, but in contrast to protests last week, there were only a few unarmed police officers on duty.

Our reporter says some people were wearing black to mourn the loss of the tombs.

Mourner Mpiima William told the BBC he was going to spend the whole week at the site. "We are not going to work before we accomplish this business," he said.

He also said he was ready to sell his possessions to help fund the restoration of the 19th Century mausoleum at Kasubi - a Unesco world heritage site.

The government has said it will help rebuild the site and Baganda ministers are discussing the plans.

It remains unclear what started the fire, although some suspect arson.

Buganda is the largest of Uganda's four ancient kingdoms; abolished in 1966 but reinstated by President Yoweri Museveni's government in 1993.

However, he restored them only as cultural institutions with no political power. Supporters of King Ronald believe he should have more power and influence than Mr Museveni allows.